To block messages from everyone who is not on your contact list or on your Allow List:
In the Messenger main window, click the Tools menu, click Options, and then click the Privacy tab.
Under My Allow List, click All others, and then click Block. All others moves to your Block list. This forces anyone who wants to send you messages to add you to their own contact list.
To block messages from an individual:
Click Block on the toolbar in the Conversation window.
If you are in a conversation with multiple people, click Block and then click the name of the person you want to block.
Notes:
The blocked contact does not know he or she has been blocked. You simply appear to be offline to them.
Deleting a blocked person from your contact list does not remove the block.
A person you have blocked cannot contact you directly; however, you might find yourself in a conversation with the blocked person if you are both invited to the conversation by someone else.
